Process of metal-casting.



H. L. WHITTEMORE.

PROCESS OF METAL CASTING.

APPLIOATION FILED MAY 14, 1910.

1,002,889, v Patented Sept. 12, 1911.

2 SHEETS-SHEET 1.

Witnesses: [nvemtaf COLUMBIA- PLANOGEAPH C0,, WASHINGTON D c H. L.WHITTEMORE. PROCESS OF METAL CASTING.

APPLIOATION FILED MAY 14, 1910.

Patented Sept. 12,1911.

w a v lam A t tarrwg/s COLUMBIA PLANOGRAPH c0.,wAsHlNaTON, B. c.

HERBERT I. VI'I-IITTEMORE, OF URBANA, ILLINOIS.

PROCESS OF METAL-CASTING.

Specification of Letters Patent.

Patented Sept. 12, 1911.

Application filed May 14, 1910. Serial No. 561,291.

To all whom it may concern:

Be it known that I, HERBERT L. WI-IITTE- MORE, a citizen of the UnitedStates, residing at Urbana, in the county of Champaign and State ofIllinois, have invented a certain new and Improved Process of Metal-Casting, of which the following is a clear, concise, and exactdescription, reference being had to the accompanying drawings, forming apart of this specification.

My invention consists in an improved process of metal casting.

It involves a combination of steps commencing with a form used in makingthe pattern continuing with the formation of the pattern itself andconcluding with the making of a sand mold into which the molten metal ispoured.

In accordance with the improved process of my invention a form is firstmade of a suitable plastic material, of which paraflin wax is the bestexample known to me. Paraiiin is easily melted. It may be readily out orshaped by means of tools and it hardens at ordinary temperatures so asto maintain the shape which is given to it in the forming process. Thiswax form thus produced is in the shape of an intaglio of the article tobe cast. The surface of the paraiiin in which the intaglio is formed ispreferably conformed also to duplicate the gate and parting surface ofthe mold which ultimately is to be made from the finished pattern. henthe form has been completed hydraulic cement, or concrete of hydrauliccement is placed in the intaglio of the article to be cast and of thegate thus to make a pattern not only of the article to be cast butpreferably also of the gate and parting surface of the mold. When theconcrete sets or hardens there results a hard durable pattern which is areverse of the sand mold into which the molten metal is to be poured incasting. The pattern duplicates not only the article to be cast but alsothe gate or gates leading from the sprues or risers and also the partingsurface of the mold. When the pattern has hardened sufficiently it isremoved from the form and by means of suitable registering devices, suchas dowels and dowel pins, it is made to occupy the desired position inthe flask into which the sand is tamped to form the sand mold. If thearticle to be cast lies entirely upon one side of the parting surface,an intaglio of the whole of the article to be cast will be cut in oneform. having been brought into register with the drag of the flask willserve to form the sand which isthen tamped into the drag to conform withthe article to be cast except that the parting surface of the cope musthave a plane surface to come into juxtaposition with the part-ingsurface of the sand of the drag, and this plane surface may be formedagainst the plane molding board o-r against the plane pattern ofconcrete as may be preferred. If on the other hand the article to becast lies partly on either side of the parting surface, a separatepattern is required for each portion of the mold. In a two-part mold asecond portion will be made in the manner above described with respectto the portion of the pattern which is used in the drag. This secondpattern will be cast in concrete from a wax form which is cut into anintaglio of the portion of the article to be cast which extends abovethe parting surface of the mold and thus into the cope of the flask. Thecope pattern is brought into register with the cope of the flask in thesame way that the other port-ion of the pattern is broughtinto registerwith the drag. Molding sand is then tamped into the cope to form thecope portion of the mold. The two portions of the mold when completedare brought into register by means of dowels or other registeringdevices to form a complete sand mold into which the molten metal to becast is poured. These and the other features of my invention will bemore clearly understood by reference to the accompanying drawings inwhich Figure 1 shows partially in side view and partially in crosssection the article to be cast. Fig. 2 is a sectional view of an intaglio of the portion of the article shown in Fig. 1 located below theparting surface. Fig. 8 is a sectional view of the intaglio shown inFig. 2 with the concrete in place to form a pattern corresponding withthe intaglio shown in Fig. 2. Fig. 4 is a cross sectional view throughthe pattern shown in Fig. 3 showing the drag of the flask in place uponthe pattern to make the portion of the mold corresponding with thisportion of the pattern. Fig. 5shows in cross sectional view an intaglioof a portion of the article to be cast shown in Fig. 1 above the partingline. Fig. 6 is a cross sectional view The pattern in this case of theintaglio shown in Fig. 5 in use to form the corresponding pattern inconcrete.

Fig. 7 is a cross sectional view of the pattern shown in Fig. 6 in useto form the corresponding portion of the mold in the cope of the flask.Fig. 8 is a view of the assembled cope and drag shown in Figs. 7 and 4which together constitute the completed mold.

Similar numerals refer to similar parts throughout the several views.

As shown in the drawings the article to be cast is a small pulley havingan overhanging rim a and a hub portion Z) projecting on either side of aweb 0 as indicated in Fig. 1. It will be understood, of course, that thearticle to be cast may have holes or other parts for which the mold isto be cored. The illustration of such complications is, however,unnecessary to the complete understanding of my invention by thoseskilled in the art.

The first step in the process consists in forming as much of an intaglioof the article to be cast as lies upon one side of the parting surfacethat is to be made in the mold. This form is made in a block of paraffinwax which, by means of suitable tools, is cut to form an intaglio of theportion of the article lying upon say the drag side of the partingsurface of the mold. The formation of this intaglio may be accomplishedpartly by melting the paraffin with hot tools if such a method ofworking is convenient to the making of the particular form required, orit may be done by hand or machine tools such as chisels, gouges, drills,milling machine, shaper, etc. In the present instance the block ispreferably mounted upon the face plate of a lathe and the intaglio 2 isformed by turning out with suitable tools the conformation of thatportion of the article shown in Fig. 1 which is below the parting line33. After this is done a gate 14: is

,formed terminating in an enlarged portion 5 which is to occupy aposition in the completed mold at the bottom of the sprue hole. Dowelpins 6 are secured in the block 1 to effect a suitable registry betweenthe drag of the flask and the pattern to be made from the intaglio 2.

The completed form 1 has placed upon it in the second step of theprocess a box 7 7 into which concrete of hydraulic cement 'is poured andcompacted when in plastic or semi-fluid condition thus to form a pattern8. Reinforcing wires or rods may be embedded in this concrete to givestiffness to narrow or slender ledges or parts of the pattern or tostiffen the body of the pattern 8. This pattern may also be given therequisite strength by making it somewhat thicker than. would be requiredfor the purposes of the pattern alone, After being filled into the box 7and the depressions of the form 1 the concrete is left until it has setso as to parting line 3-3.

retain the formation of the intaglio 2. The box 7 is then removed andthe pattern 8 is removed from the form 1 as a result of which thatportion of the article below the parting line 3-3 of Fig. l isreproduced in the pattern 8 together with the gate for the mold to bemade from the pattern. The surface of the pattern 8 which surrounds theoutlines of the article to be cast is adapted to form the partingsurface of the mold. Dowel pins 6 form holes in the pattern 8, thesebeing adapted for engagement by registering dowel pins 9 carried by thedrag 10 of the flask as shown in Fig. 4.

Not only is a form made for the casting of the drag portion of thepattern but a form and concrete pattern are in like manner made tocorrespond with the portion of the article which is molded in the cope.This form 11 is illustrated in Fig. 5, it being apparent that there iscut in this form an intaglio corresponding with the portion of thearticle of Fig. 1 which lies above the This form 11. has also placed init pins 12 upon which to register the cope of the flask, when placedupon the pattern. A pin 13 is also placed in the form as shown in Fig. 6in order to locate the sprue in forming the cope of the mold.

When the form 11 is finished a box 14.- is placed upon its upper surfaceas shown in Fig. 6 and this is filled with concrete in plasticcondition. When the concrete has hardened the box 1 1 like the box 7 mayor may not be removed as is preferred. The concrete pattern 15 is,however, removed from the form 11, the pins 12 in this case beingretained in the pattern. The pin 13 is removed from the pattern 15 so asto leave a centering opening or hole for the pin 13 carried at the lowerend of the sprue former 16 as shown in Fig. 7.

After the patterns have become thoroughly hard and dry they are adaptedfor use in making thesand molds. I have found that a concrete ofhydraulic cement is given a very hard and smooth surface when cast incontact with a form of paraflin wax. It is an easy matter to give thewax intaglio a smooth glossy finish and the smoothness and evenness ofthis surface is imparted to the concrete pattern itself. Furthermore thepattern is easily separated from the wax form. Should any of theparaffin of the form cling to crevices of the pattern the application ofslight heat will melt the wax so that it may run off the pattern.

Fig. 4 shows the drag 10 of a flask in register with the pattern 8. Thedrag is then filled and tamped with moist molding sand in the usual way.The bot-tom is struck off flush with the bottom edge of the flask 10, amolding board is applied and the pattern and drag are together turnedover when the pattern may be drawn from the drag leaving this portion ofthe mold complete. In like manner the pattern 15 for the cope part ofthe mold is placed upon the floor as shown in Fig. 7. The cope 17 of theflask is applied as shown, the pins 12 being brought into register withthe brackets 18 and the sprue former being placed in proper positionupon the center formed in the concrete pattern. The cope 17 is thenfilled with molding sand which is tamped into place. The sprue former 16is then withdrawn. The cope filled with sand is lifted from the pattern,or if necessary the cope with the pattern may be turned over upon thefloor and the pattern lifted from the top of the cope after which thecope is placed upon the top of the drag as shown in Fig. 8 the two beingbrought into register with one another by means of the dowel pins 9 andthe brackets 18 as shown.

The completed mold with its flask is placed upon the board 19 when themold is ready for the molten iron or other metal to be poured tocomplete the casting operation.

While I have described my invention in connection with the particularmaterials and arrangements herein disclosed, I do not, however, limitmyself to these precise details, but desire to claim broadly anyequivalent steps which may suggest themselves to those skilled in theart.

lVhat I claim is:

1. The process of metal casting which consists in cutting in paraffinwax an intaglio of the article to be cast, filling the intaglio with aconcrete of hydraulic cement in fluid or plastic condition, causing theconcrete to set to form a hard pattern, removing the pattern from thewax intaglio, surrounding the pattern with tamped molding sand in asuitable flask, drawing the pattern from the sand mold, closing the moldand pouring into it the molten metal to be cast.

2. The process of metal casting which consists in first carving anintaglio of the article to be cast, filling the intaglio with concretein plastic condition, causing the concrete to set to form a pattern,removing the pattern from the intaglio, ramming a mold of molding sandin contact with the said pattern, drawing the pattern from the sandmold, and metal.

3. The process of metal casting which consists in first forming inparafiin wax an int-aglio of the portion of the article to be casttogether with a parting surface, similarly forming in paraffin wax asecond intaglio of another portion of the article to be cast and acorresponding parting surface, filling each of the intaglio wax formswith concrete in a plastic state to cover both the intaglio and theparting surface of each form, causing the concrete to solidify to formsectional patterns, removing each sectional pattern from its waxintaglio, ramming the drag of a flask with molding sand in contact withone of the sectional patterns, ramming the cope of the flask withmolding sand in contact with the other sectional pattern, drawing thesectional patterns from the drag and the cope respectively, bringing thecope and the drag of the flask into register with each other, theparting surface of the cope being brought into contact with the partingsurface of the drag, and pouring the sand mold with metal to be cast.

4. The process of metal casting which consists in first carving anintaglio of the article to be cast in a block of wax, the surface of theblock corresponding to the parting surface of the mold to be formed,casting a concrete pattern and block in contact with said wax block andintaglio, preparing a drag of molding sand from said pattern and block,carving an intaglio of the article to be cast above the line of theparting surface in a block of wax, the surface of this second blockcorresponding to the parting surface of the mold to be formed, moldin aconcrete pattern and block by means of tiis second wax block, reparing acope of molding sand from said second-named pattern and block,associating said cope and drag to form a mold, and pouring molten metalinto said mold.

In witness whereof, I hereunto subscribe my name this sixth day of May,A. D. 1910.

HERBERT L. WHITTEMORE.

Witnesses: I

JAMES W. WEBBER, T. B. WEBBER.

pouring the mold with molten Copies of this patent may be obtained forfive cents each, by addressing the Commissioner of Patents, Washington,D. G.

